Structure for preventing thermal damage to active noise control speaker

ABSTRACT

A structure for preventing thermal damage to an active noise control speaker includes: an exhaust pipe; a muffler; a speaker in a speaker housing disposed adjacent and connected to the exhaust pipe and the muffler that produces an acoustic wave having a phase that is reverse to a phase of a frequency of the exhaust sound of the exhaust gas; a speaker tube through which low-temperature wind flows into and out of the speaker housing; and an expanded tube portion connected to the speaker tube at an outer circumferential surface thereof, and has a cross-sectional area larger than a cross-sectional area of the speaker tube, in which heated air is discharged from the speaker housing thereby decreasing a temperature of the speaker, thereby improving performance of outputting an acoustic wave of the speaker in comparison with a case in which a temperature of the speaker is high.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority of Korean Patent Application Number 10-2013-0098419 filed Aug. 20, 2013, the entire contents of which application is incorporated herein for all purposes by this reference.

BACKGROUND OF INVENTION

1. Field of Invention

The present invention relates to an active noise control speaker, and more particularly, to a structure for preventing thermal damage to an active noise control speaker which includes a speaker tube having an inlet and an outlet so that low-temperature wind generated by running the vehicle flows into and out of a speaker housing, and an expanded tube portion which is connected to the speaker tube by a fixing portion formed on an outer circumferential surface of the speaker tube and has a cross-sectional area larger than a cross-sectional area of the speaker tube, in which heated air in the speaker housing is discharged.

2. Description of Related Art

Noise, which enters an interior of a vehicle, is generated by various factors such as an operation of an engine, unevenness of a road surface, or sound of wind that flows in when the vehicle runs, and various devices for reducing the noise are used. Particularly, in order to reduce discharge noise of exhaust gas, which is generated at an exhaust pipe of the vehicle, a separate muffler is mounted on an exhaust gas passage of the vehicle.

In general, as a method of reducing exhaust sound of exhaust gas, there are a manual noise control method which utilizes a muffler for reducing noise by applying back pressure using complicated structures such as baffles, pipes, and variable valves that are disposed on an exhaust gas flow passage, and an active noise control (ANC) method which reduces noise of exhaust gas by producing an acoustic wave, which has the same frequency as noise of exhaust gas and has a reverse phase, and by offsetting noise of exhaust gas with the acoustic wave.

Particularly, recently, the active noise control method, which provides a more comfortable and quiet environment to a customer of the vehicle and has an excellent effect in attenuating low-frequency noise, is in the limelight, in comparison with the manual noise control method in which efficiency significantly deteriorates when noise of exhaust gas is in a low frequency region, a suitable handling method is not provided in accordance with a running speed of the vehicle, and a problem with increases in volume and cost of the muffler is caused.

An active noise controller includes a microphone which senses noise of exhaust gas, a controller which calculates and analyzes the noise sensed by the microphone, and transmits an electrical signal having a frequency with a phase that corresponds to a frequency of noise of exhaust gas to a speaker, and a speaker which regenerates the frequency having the corresponding phase.

The active noise controller uses a method that produces artificial sound, which has the same size as the sound of exhaust gas of the vehicle but has a reverse phase, through the speaker, and attenuates a level of acoustic pressure of noise or removes noise by superimposing two signals.

However, as illustrated in FIG. 1, because an active noise control speaker 3 of the related art is mounted adjacent to a high-temperature muffler 2 and an exhaust pipe 1, there is a problem in that the active noise control speaker 3 is thermally damaged by high-temperature heat generated at the muffler 2 and the exhaust pipe 1.

Because when a speaker housing 4 is hermetic, air in the speaker housing 4 hinders vibration of a speaker diaphragm, and an operation of outputting low frequency is not smoothly performed, there is a problem in that a separate port needs to be additionally installed.

In a case in which a hole for discharging air is merely and additionally formed in the speaker housing 4 in order to cool the active noise control speaker 3 of the related art, there is a problem in that foreign substances flow into the speaker housing 4, which causes deterioration of performance of the speaker 3.

The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

BRIEF SUMMARY

Various aspects of the present invention provide for a structure for preventing thermal damage to an active noise control speaker which includes a speaker tube having an inlet and an outlet so that low-temperature wind generated by running the vehicle flows into and out of a speaker housing, and an expanded tube portion which is connected to the speaker tube by a fixing portion formed on an outer circumferential surface of the speaker tube and has a cross-sectional area larger than a cross-sectional area of the speaker tube, such that thermal damage to the speaker due to a high-temperature muffler and exhaust pipe is prevented, performance of outputting low-frequency sound is improved by the speaker tube serving as a port of the speaker, and an inflow of foreign substances into the speaker housing is minimized.

Various aspects of the present invention provide for a structure for preventing thermal damage to an active noise control speaker including: an exhaust pipe which is connected to a rear side of a vehicle so as to discharge exhaust gas to the outside of the vehicle; a muffler which is disposed on the exhaust pipe and reduces exhaust sound of the exhaust gas; a speaker which is accommodated in a speaker housing, which is disposed to be adjacent to and connected to the exhaust pipe and the muffler, and produces an acoustic wave having a phase that is reverse to a phase of a frequency of the exhaust sound of the exhaust gas; a speaker tube having an inlet and an outlet so that low-temperature wind generated by running the vehicle flows into and out of the speaker housing; and an expanded tube portion which is connected to the speaker tube by a fixing portion formed on an outer circumferential surface of the speaker tube, and has a cross-sectional area larger than a cross-sectional area of the speaker tube, in which heated air in the speaker housing is discharged to the outside of the speaker housing.

In the expanded tube portion, a cross-sectional area in a direction of the inlet of the speaker tube may be formed to be larger than a cross-sectional area in a direction of the outlet of the speaker tube, and the cross-sectional area may be decreased in a direction from the inlet of the speaker tube to the outlet of the speaker tube.

A plurality of expanded tube portions may be formed on the speaker tube.

The inlet of the speaker tube may be formed in an outer surface of the speaker housing so as to be directed toward a front side of the vehicle, and the outlet of the speaker tube may be formed in the outer surface of the speaker housing so as to be directed toward a rear side of the vehicle.

The fixing portions may be formed on the outer circumferential surface of the speaker tube so as to be radially and symmetrically spaced apart from each other on the basis of a center of the speaker tube.

Various aspects of the present invention provide for a structure for preventing thermal damage to the active noise control speaker that includes a speaker tube having an inlet and an outlet so that low-temperature wind generated by running the vehicle flows into and out of a speaker housing, and an expanded tube portion which is connected to the speaker tube by a fixing portion formed on an outer circumferential surface of the speaker tube and has a cross-sectional area larger than a cross-sectional area of the speaker tube, in which heated air in the speaker housing is discharged to the outside of the speaker housing, thereby preventing thermal damage to the speaker that is mounted adjacent to a high-temperature muffler and exhaust pipe.

The expanded tube portion may be formed in a funnel shape in which a cross-sectional area in a direction of the inlet of the speaker tube is formed to be larger than a cross-sectional area in a direction of the outlet of the speaker tube, and the cross-sectional area is decreased in a direction from the inlet of the speaker tube to the outlet of the speaker tube, such that an occurrence of back flow of wind generated by running the vehicle into the speaker housing may be minimized, and performance of discharging heated air in the speaker housing may be improved.

The inlet of the speaker tube may be formed in an outer surface of the speaker housing so as to be directed toward a front side of the vehicle, and the outlet of the speaker tube is formed in the outer surface of the speaker housing so as to be directed toward a rear side of the vehicle, such that wind generated by running the vehicle may more efficiently flow into and out of the speaker housing, and heated air in the speaker housing may also be effectively discharged, thereby improving cooling performance of the speaker.

The fixing portions may be formed on the outer circumferential surface of the speaker tube so as to be radially and symmetrically spaced apart from each other on the basis of a center of the speaker tube, such that air in the speaker housing may uniformly flow into the speaker tube, and the speaker tube may be kept in balance.

As a result, in the structure for preventing thermal damage to the active noise control speaker according to the present invention, high-temperature air may be discharged to the outside of the speaker housing, such that a temperature of the speaker is decreased, thereby improving performance of outputting an acoustic wave of the speaker in comparison with a case in which a temperature of the speaker is high.

There is a probability that external foreign substances may flow in when a hole for discharging air is merely and additionally formed in the speaker housing, but in the structure for preventing thermal damage to the active noise control speaker according to the present invention, an inflow of foreign substances may be minimized by flows of wind generated by running the vehicle and air in the speaker housing according to shapes of the speaker tube and the expanded tube portion.

The speaker tube may serve as the inlet and the outlet for wind generated by running the vehicle, and simultaneously, serves as a port of the speaker, thereby improving performance of outputting low-frequency sound of the speaker without adding a separate port.

The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating an aspect of an active noise controller.

FIG. 2 is a top plan view illustrating an exemplary structure for preventing thermal damage to an active noise control speaker according to the present invention.

FIG. 3 is a perspective view illustrating the exemplary structure for preventing thermal damage to the active noise control speaker according to the present invention.

FIG. 4 is an enlarged view illustrating aspects of a tube and an expanded tube portion of the exemplary structure for preventing thermal damage to the active noise control speaker according to the present invention.

FIG. 5 is a cross-sectional view taken along line A-A′ of FIG. 4.

FIG. 6 is a cross-sectional view taken along line B-B′ of FIG. 4.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.

A structure for preventing thermal damage to an active noise control speaker according to the present invention includes an exhaust pipe 10 which is connected to a rear side of a vehicle so as to discharge exhaust gas to the outside of the vehicle, a muffler 20 which is disposed on the exhaust pipe 10 and reduces exhaust sound of exhaust gas, a speaker 30 which is accommodated in a speaker housing 32, which is disposed to be adjacent to and connected to the exhaust pipe 10 and the muffler 20, and produces an acoustic wave having a phase that is reverse to a phase of frequency of exhaust sound of exhaust gas, a speaker tube 40 having an inlet 42 and an outlet 44 so that low-temperature wind generated by running the vehicle flows into and out of the speaker housing 32, and an expanded tube portion 50 which is connected to the speaker tube 40 by a fixing portion 52 formed on an outer circumferential surface of the speaker tube 40 and has a cross-sectional area larger than a cross-sectional area of the speaker tube 40, in which heated air in the speaker housing 32 is discharged to the outside of the speaker housing 32.

As illustrated in FIG. 2, the muffler 20 is connected to a passage through which exhaust gas flows into the exhaust pipe 10 of the vehicle, and typically disposed at the rear side of the vehicle.

The muffler 20 is primarily utilized to reduce exhaust noise of exhaust gas, and similarly to a configuration of a muffler of the related art, the muffler 20 includes therein constituent elements such as a baffle, a pipe, and a variable valve.

As illustrated in FIG. 2, the speaker housing 32 is connected to the exhaust pipe 10, disposed adjacent to a rear end of the muffler 20, and thus disposed in the form that is entirely enclosed by the high-temperature exhaust pipe 10 and the muffler 20.

The speaker 30 is mounted in the speaker housing 32, and the speaker 30 is utilized to sense exhaust sound of exhaust gas using a microphone and to produce an acoustic wave having a phase which has the same size as a phase of frequency of exhaust sound of exhaust gas but having a reverse phase.

As illustrated in FIGS. 2 and 3, the speaker tube 40 including the inlet 42 through which low-temperature wind generated by running the vehicle flows in, and the outlet 44 through which wind generated by running the vehicle flows out, is accommodated in the speaker housing 32.

In various embodiments, the speaker tube 40 is mounted in a space between an inner surface of the speaker housing 32 and the speaker 30, and the inlet 42 and the outlet 44 protrude to the outside of the speaker housing 32 so that low-temperature wind generated by running the vehicle flows in and out.

As illustrated in FIG. 3, the expanded tube portion 50, which is connected to the speaker tube 40 by the fixing portion 52 formed on the outer circumferential surface of the speaker tube 40 and has a cross-sectional area larger than a cross-sectional area of the speaker tube 40, is coupled on the speaker tube 40.

The expanded tube portion 50 may be formed in a cylindrical shape having a cross-sectional center that is the same as a cross-sectional center of the speaker tube 40, and may be formed in various shapes such as a quadrangular container shape, or a plate shape, which is coupled to the speaker tube, in accordance with required cooling performance of the speaker, a position of the speaker housing, a shape of the speaker tube, or the like.

The expanded tube portion 50 is connected to the speaker tube 40 by the fixing portion 52 formed on the outer circumferential surface of the speaker tube 40, and heated air in the speaker housing 32 flows into the speaker tube 40 through the remaining space portion 54 except for the fixing portion 52 and then is discharged to the outside of the speaker housing 32.

That is, air pressure inside the speaker tube 40 becomes lower than air pressure outside the speaker tube 40 by wind generated by running the vehicle that flows into the speaker tube 40, and depending on the difference in air pressure, heated air in the speaker housing 32 flows into the speaker tube 40 through the space portion 54 of the expanded tube portion 50 and then is discharged to the outside of the speaker housing 32.

As illustrated in FIG. 4, in the expanded tube portion 50, a cross-sectional area in a direction of the inlet 42 of the speaker tube 40 may be formed to be larger than a cross-sectional area in a direction of the outlet 44 of the speaker tube 40, and the cross-sectional area may be decreased in a direction from the inlet 42 of the speaker tube 40 to the outlet 44 of the speaker tube 40.

That is, the expanded tube portion 50 may be entirely formed in a funnel shape such that heated air in the speaker housing 32 easily flows into the speaker tube 40, and wind generated by running the vehicle in the speaker tube 40 does not flow into the speaker housing 32.

Since the expanded tube portion 50 is formed in a funnel shape, an occurrence of back flow of wind generated by running the vehicle in the speaker housing 32 is minimized, thereby improving performance of discharging heated air and minimizing an inflow of foreign substances into the speaker housing 32.

As illustrated in FIG. 4, a plurality of expanded tube portions 50 may be formed on the speaker tube 40.

Since the plurality of expanded tube portions 50 is formed on the speaker tube 40, heated air in the speaker housing 32 may be maximally discharged in comparison with a case in which a single expanded tube portion 50 is formed on the speaker tube 40, and therefore, the speaker 30 may be effectively cooled, thereby maximally improving performance of the speaker 30.

In various embodiments, five expanded tube portions 50 are formed on the speaker tube 40, but it is apparent that various numbers of expanded tube portions 50 may be formed in accordance with required cooling performance of the speaker, a length of the speaker tube, a size of the expanded tube portion, or the like.

As illustrated in FIGS. 2 and 3, the inlet 42 of the speaker tube 40 may be formed in an outer surface of the speaker housing 32 so as to be directed toward a front side of the vehicle, and the outlet 44 of the speaker tube 40 may be formed in the outer surface of the speaker housing 32 so as to be directed toward a rear side of the vehicle.

Specifically, as illustrated in FIG. 2, the inlet 42 of the speaker tube 40 is formed in an upper portion of the outer surface of the speaker housing 32 in a tangential direction of the speaker housing 32 so as to be directed toward the front side of the vehicle. That is, the inlet 42 of the speaker tube 40 is formed at a position where low-temperature wind generated by running the vehicle is most easily received.

As illustrated in FIG. 3, in various embodiments, the outlet 44 of the speaker tube 40 is formed in a right and upper portion of the outer surface of the speaker housing 32 so as to be directed toward the rear side of the vehicle. That is, the outlet 44 of the speaker tube 40 is formed at a position where wind generated by running the vehicle is most smoothly discharged.

As illustrated in FIG. 4, the fixing portions 52 may be formed on the outer circumferential surface of the speaker tube 40 so as to be radially and symmetrically spaced apart from each other on the basis of a center of the speaker tube 40.

In various embodiments, four fixing portions 52 are formed on the outer circumferential surface of the speaker tube 40 so as to be spaced apart from each other at an angle of 90°, and the fixing portions 52 are radially and symmetrically formed, such that heated air in the speaker housing 32 uniformly flows into the space portion 54 of the expanded tube portion 50, thereby maintaining balance of the speaker tube 40 without causing the speaker tube 40 to be shaken.

It can be seen by those skilled in the art that various numbers of fixing portions 52 may be formed as long as the fixing portions 52 are formed on the outer circumferential surface of the speaker tube 40 so as to be radially and symmetrically spaced apart from each other.

An operational process according to various embodiments of the present invention will be described below.

The muffler 20 and the exhaust pipe 10 are heated by high-temperature exhaust gas that is discharged when the vehicle runs, and the speaker housing 32, which is disposed adjacent to the muffler 20 and the exhaust pipe 10, is also heated by heat of the muffler 20 and the exhaust pipe 10.

In this case, as illustrated in FIG. 5, low-temperature wind generated by running the vehicle and flowing in through the inlet 42 of the speaker tube 40, which protrudes to the outside of the speaker housing 32, flows in the interior of the speaker tube 40, and then is discharged through the outlet 44 of the speaker tube 40.

As illustrated in FIG. 6, since the low-temperature wind generated by running the vehicle flows into the speaker tube 40, air pressure, which is lower than air pressure at the exterior of the speaker tube 40, is formed in the interior of the speaker tube 40, and therefore, heated air in the speaker housing 32 flows into the speaker tube 40 through the space portion 54 of the expanded tube portion 50.

The heated air flowing into the speaker tube 40 flows in the interior of the speaker tube 40 and then is discharged to the outside of the speaker housing 32 through the outlet 44 of the speaker tube 40, and depending on the discharge of the heated air in the speaker housing 32, a temperature of the speaker 30 is decreased, thereby improving performance of outputting an acoustic wave of the speaker 30.

The speaker tube 40 simultaneously serves as a speaker port, thereby resolving a problem that low frequency may not be smoothly outputted because air in the speaker housing 32 hinders vibration of a speaker diaphragm when the speaker housing 32 is hermetic.

For convenience in explanation and accurate definition in the appended claims, the terms upper, front or rear, and etc. are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents. 

What is claimed is:
 1. A structure for preventing thermal damage to an active noise control speaker, comprising: an exhaust pipe connected to a rear side of a vehicle so as to discharge exhaust gas to the outside of the vehicle; a muffler disposed on the exhaust pipe and reduces exhaust sound of the exhaust gas; a speaker disposed in a speaker housing adjacent and connected to the exhaust pipe and the muffler, wherein the speaker produces an acoustic wave having a phase that is reverse to a phase of a frequency of the exhaust sound of the exhaust gas; a speaker tube having an inlet and an outlet through which a low-temperature airflow generated as the vehicle moves, the speaker tube directing the airflow into and out of the speaker housing; and an expanded tube portion connected to the speaker tube by a fixing portion formed on an outer circumferential surface of the speaker tube, the expanded tube portion having a cross-sectional area larger than a cross-sectional area of the speaker tube; wherein air heated in the speaker housing is discharged from the speaker housing.
 2. The structure of claim 1, wherein in the expanded tube portion, a cross-sectional area in a direction of the inlet of the speaker tube is formed to be larger than a cross-sectional area in a direction of the outlet of the speaker tube, and the cross-sectional area is decreased in a direction from the inlet of the speaker tube to the outlet of the speaker tube.
 3. The structure of claim 1, wherein a plurality of expanded tube portions is formed on the speaker tube.
 4. The structure of claim 1, wherein the inlet of the speaker tube is formed in an outer surface of the speaker housing directed toward a front side of the vehicle, and the outlet of the speaker tube is formed in the outer surface of the speaker housing directed toward a rear side of the vehicle.
 5. The structure of claim 1, wherein the fixing portions are formed on the outer circumferential surface of the speaker tube radially and symmetrically spaced apart from each other on the basis of a center of the speaker tube. 